"""
同一性判断符
"""

def testIsInstance():
    # is 和 == 非常相似
    # is 主要比较的是对象的唯一id是否相同
    # == 比较的是值是否相同

    a = [1,2,3]
    b = [1,2,3]
    copya = a

    print(" copya is a --> {}".format(copya is a))

    print("a is b --> {}".format(a is b))

    print("a == b is {}".format(a == b))

    print("a == copya is {}".format(a == copya))

    print("b == copya is {}".format(b == copya))

    print("a is not b --> {}".format(a is not b))


testIsInstance()